1. Field of the Invention
The invention concerns graphical displays in computer systems in general and graphical displays of the results of queries in particular.
2. Description of the Prior Art
As computers have become cheaper and more powerful, interactive data base systems have become widely available. Users in many different areas of endeavor employ interactive data base systems to find items of information in a large collection of information. A user of an interactive data base system provides the data base system with a query which the user believes will describe the items of information being sought. The data base system then responds to the query by returning a result which includes all of the information in the data base system which satisfies the query. The result generally also includes a value which indicates the number of hits, that is, the number of items of data which satisfy the query.
FIG. 1 is a block diagram of an example interactive data base system 101. The system includes terminal 103, which provides output to and receives input from the user, processor 113, which performs the actual searching operations, and memory system 115, which contains programs 119 executed by processor 113 and data base 117 which contains the data. In more detail, terminal 103 includes a display screen 105, upon which processor 113 displays information for the user. Display screen 105 also includes pointer 107, which specifies a location in display 105 and may be moved under control of either keyboard 109 or mouse 111. The user controls the operation of system 101 by inputs from keyboard 109 and/or mouse 111. Processor 113 may be any kind of processor, from a personal computer through a supercomputer. Memory system 115, finally, includes any data accessible to system 101, and may thus include random-access memory, a file system on magnetic or optical disk, or even remotely-located data bases. When employing system 101 to find information in data base 117, the user inputs a query using keyboard 109 or mouse 111; processor 113 executes programs 119 as required to perform the query on data base 117 and returns the number of hits and the results to display screen 105. The user can then use keyboard 109 and/or mouse 111 to examine the results in more detail.
The usefulness of interactive data base systems like system 101 is attested to by their popularity; present systems do, however, have their limitations. A recurring source of frustration among users of interactive data base systems is that the systems always seem to return either too little or too much information. A user is typically looking for a half a dozen good pieces of information; queries typically produce no hits or a hundred; when the query produces no hits, the user must broaden it, whereupon it produces hundreds; when it produces too many, the user must narrow it, whereupon it produces no hits. Very often, even experienced users are at a loss to find a query which will produce a useful number of hits.
The problems caused by large numbers of hits are aggravated by the fact that interactive data base systems typically only specify the number of hits, and thus provide no information which the user can take advantage of to subdivide the collection of hits. This tendency to treat the hits as a "black bag" also makes it difficult to use interactive data base systems to investigate questions like the relationship of the hits to a period of time or to a set of authors. It is an object of the invention to solve these and other problems of interactive data base systems.